/*
 * Copyright (c) 2014, Peter Thorson. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the WebSocket++ Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef WEBSOCKETPP_LOGGER_BASIC_HPP
#define WEBSOCKETPP_LOGGER_BASIC_HPP

/* Need a way to print a message to the log
 *
 * - timestamps
 * - channels
 * - thread safe
 * - output to stdout or file
 * - selective output channels, both compile time and runtime
 * - named channels
 * - ability to test whether a log message will be printed at compile time
 *
 */

#include <websocketpp/logger/levels.hpp>

#include <websocketpp/common/cpp11.hpp>
#include <websocketpp/common/stdint.hpp>
#include <websocketpp/common/time.hpp>

#include <ctime>
#include <iostream>
#include <iomanip>
#include <string>

namespace websocketpp
{
namespace log
{

/// Basic logger that outputs to an ostream
template <typename concurrency, typename names>
class basic
{
public:
  basic<concurrency, names> (channel_type_hint::value h =
                               channel_type_hint::access)
    : m_static_channels (0xffffffff)
    , m_dynamic_channels (0)
    , m_out (h == channel_type_hint::error ? & std::cerr : & std::cout) {}

  basic<concurrency, names> (std::ostream *out)
    : m_static_channels (0xffffffff)
    , m_dynamic_channels (0)
    , m_out (out) {}

  basic<concurrency, names> (level c, channel_type_hint::value h =
                               channel_type_hint::access)
    : m_static_channels (c)
    , m_dynamic_channels (0)
    , m_out (h == channel_type_hint::error ? & std::cerr : & std::cout) {}

  basic<concurrency, names> (level c, std::ostream *out)
    : m_static_channels (c)
    , m_dynamic_channels (0)
    , m_out (out) {}

  /// Destructor
  ~basic<concurrency, names>() {}

  /// Copy constructor
  basic<concurrency, names> (basic<concurrency, names> const &other)
    : m_static_channels (other.m_static_channels)
    , m_dynamic_channels (other.m_dynamic_channels)
    , m_out (other.m_out)
  {}

#ifdef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
  // no copy assignment operator because of const member variables
  basic<concurrency, names> &operator= (basic<concurrency, names> const &) =
    delete;
#endif // _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_

#ifdef _WEBSOCKETPP_MOVE_SEMANTICS_
  /// Move constructor
  basic<concurrency, names> (basic<concurrency, names>  &&other)
    : m_static_channels (other.m_static_channels)
    , m_dynamic_channels (other.m_dynamic_channels)
    , m_out (other.m_out)
  {}

#ifdef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
  // no move assignment operator because of const member variables
  basic<concurrency, names> &operator= (basic<concurrency, names> && ) = delete;
#endif // _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_

#endif // _WEBSOCKETPP_MOVE_SEMANTICS_

  void set_ostream (std::ostream *out = &std::cout)
  {
    m_out = out;
  }

  void set_channels (level channels)
  {
    if (channels == names::none) {
      clear_channels (names::all);
      return;
    }

    scoped_lock_type lock (m_lock);
    m_dynamic_channels |= (channels & m_static_channels);
  }

  void clear_channels (level channels)
  {
    scoped_lock_type lock (m_lock);
    m_dynamic_channels &= ~channels;
  }

  /// Write a string message to the given channel
  /**
   * @param channel The channel to write to
   * @param msg The message to write
   */
  void write (level channel, std::string const &msg)
  {
    scoped_lock_type lock (m_lock);

    if (!this->dynamic_test (channel) ) {
      return;
    }

    *m_out << "[" << timestamp << "] "
           << "[" << names::channel_name (channel) << "] "
           << msg << "\n";
    m_out->flush();
  }

  /// Write a cstring message to the given channel
  /**
   * @param channel The channel to write to
   * @param msg The message to write
   */
  void write (level channel, char const *msg)
  {
    scoped_lock_type lock (m_lock);

    if (!this->dynamic_test (channel) ) {
      return;
    }

    *m_out << "[" << timestamp << "] "
           << "[" << names::channel_name (channel) << "] "
           << msg << "\n";
    m_out->flush();
  }

  _WEBSOCKETPP_CONSTEXPR_TOKEN_ bool static_test (level channel) const
  {
    return ( (channel & m_static_channels) != 0);
  }

  bool dynamic_test (level channel)
  {
    return ( (channel & m_dynamic_channels) != 0);
  }

protected:
  typedef typename concurrency::scoped_lock_type scoped_lock_type;
  typedef typename concurrency::mutex_type mutex_type;
  mutex_type m_lock;

private:
  // The timestamp does not include the time zone, because on Windows with the
  // default registry settings, the time zone would be written out in full,
  // which would be obnoxiously verbose.
  //
  // TODO: find a workaround for this or make this format user settable
  static std::ostream &timestamp (std::ostream &os)
  {
    std::time_t t = std::time (NULL);
    std::tm lt = lib::localtime (t);
#ifdef _WEBSOCKETPP_PUTTIME_
    return os << std::put_time (&lt, "%Y-%m-%d %H:%M:%S");
#else // Falls back to strftime, which requires a temporary copy of the string.
    char buffer[20];
    size_t result = std::strftime (buffer, sizeof (buffer), "%Y-%m-%d %H:%M:%S",
                                   &lt);
    return os << (result == 0 ? "Unknown" : buffer);
#endif
  }

  level const m_static_channels;
  level m_dynamic_channels;
  std::ostream *m_out;
};

} // log
} // websocketpp

#endif // WEBSOCKETPP_LOGGER_BASIC_HPP
